Yes, but in case of SPEC you cannot recode so the improvements only can be obtained through compilation.


Vincent Diepeveen (diep@xs4all.nl) on 6/22/03 wrote:
---------------------------
>In short we can definitely say that there is performance differences, but usually
>good programmers can optimize very well and get around it.
>
>But to give some examples:
>
>example a) you run 4 processes at a single cpu and they are mutually locking.
>
>In windows you implement it for example with the well known WaitForSingleObject()/WaitForMultipleObject().
>
>In Linux you lock as it has no WaitForSingleObject().
>
>In IRIX you also lock using spin_lock().
>
>Then you measure performance and linux is tens of times slower than both the other OSes.
>
>It appears then that both IRIX and windows are first trying to lock the object
>a few times in a row without putting a process into the runqueue. So if such an
>object is released within say 600 ns then the processes can run on.
>
>However under linux there is no such function for multiprocessing, so each process
>gets in the runqueue which means a 10ms latency each time, which is pretty much slower than < 600 ns :)
>
>Trivially some good programming can speedup the software at all the OSes a lot.
>
>Paul DeMone (pdemone@igs.net) on 6/22/03 wrote:
>---------------------------
>>Anonymous (nn@nn.invalid) on 6/22/03 wrote:
>>---------------------------
>>>Paul DeMone (pdemone@igs.net) on 6/20/03 wrote:
>>>---------------------------
>>>>The SPEC CPU suite programs are specifically selected and sometimes even
>>>>modified to minimize the influence of differences in OS and language libraries
>>>>across platforms.
>>>
>>>Then why is e.g. Intel's compiler for Linux showing noticeably lower performance
>>>than Intel's compiler for Windows? Last evidenced in Ace's Hardware's posting about Opteron SPEC performance:
>>>
>>>http://www.aceshardware.com/read_news.jsp?id=65000417
>>>
>>>I find it hard to believe that executable format and execution model wouldn't affect performance somewhat. :)
>>
>>I don't believe I claimed otherwise. I simply said that effort was made in the construction of each
>>SPEC CPU suite to minimize the effect of OS/library related cross platform differences. But there
>>are OS functions that cannot be avoided, like virtual memory management. Perhaps the VM code
>>in Windows is more efficient on the target machine than Linux's.
>>
>